Matthew 6:3

Vocabulary (Greek word by word)

σοῦ (pron 2nd sg gen) "When thou" is from sou which means "you" and "your".

δὲ (partic) "But" is from de which means "but" and "on the other hand". It is the particle that joins sentences in an adversarial way but can also be an explanation of cause ("so").

ποιοῦντος (part sg pres act masc gen ) "Doest" is from poieo, which means "to make", "to produce", "to create", "to bring into existence", "to bring about", "to cause", "to render", "to consider", "to prepare", "to make ready" and "to do".

ἐλεημοσύνην (noun sg fem acc) "Alms" is from a word which means "pity", "mercy", "charity" and "alms". It is the noun form of the verb eleeo, which means "to have pity on", "to show mercy to" and "to feel pity". In the passive, "to be shown pity" and "to be pitied".

μὴ (partic) "Lest" is from me, which is the negative used in prohibitions and expressions of doubt meaning "not" and "no". As οὐ (ou) negates fact and statement; μή rejects, οὐ denies; μή is relative, οὐ absolute; μή subjective, οὐ objective.

γνώτω (3rd sg aor imperat act) "Know," is from ginosko which means "to learn to know", "to know by reflection or observation" and "to perceive".

ἡ (article sg fem nom)  Untranslated is the Greek definite article, hos, ("the").

ἀριστερά [3 verses[(adj sg fem nom) "The left" is from aristeros, which means "left", "on the left", "boding ill", "ominous", "awkward", "erring" and "leftward in the mind".

σου (pron 2nd sg gen) "Thy" is from sou which means "you" and "your".

τί (irreg sg neut nom/acc) "What" is from tis which can mean "someone", "any one", "everyone", "they" [indefinite], "many a one", "whoever", "anyone", "anything", "some sort", "some sort of", "each", "any", "the individual", "such" and so on. In a question, it can mean "who", "why" or "what".

ποιεῖ (3rd sg pres ind act or 3rd sg imperf ind act ) "Doeth" is from poieo, which means "to make", "to produce", "to create", "to bring into existence", "to bring about", "to cause", "to render", "to consider", "to prepare", "to make ready" and "to do".

ἡ (article sg fem nom)  Untranslated is the Greek definite article, hos, ("the").

δεξιά (noun sg fem nom) "Right" is from dexios, which means, as an adjective, "on the right hand", "fortunate", "skillful", "ready", "clever", "courteous" and "kindly". As a noun, it means the "right hand", "assurance", "pledge" and "treaty".

σου, (pron 2nd sg gen) "Thy" is from sou which means "you" and "your".

KJV — word by word

But -- The Greek word translated as "but" joins sentences in an adversarial way or introduces a phrase explaining a cause or condition. Given the odd structure of the phrase it is in, it really works best as something like an "if" explaining an alternative condition. 

when -- (IW) There is nothing that can be translated as "when" in the Greek source.

thou -- This verse starts with a singular pronoun, "you" but its form is not that of a subject, but the form that is normally translated as "of you" or "your". This form is required by the form of the verb. The form is singular, continuing the switch to the singular "you" in the previous verse (Matthew 6:2) from the plural "you" in the verse before that (Matthew 6:1) that began this discussion of rewards for good acts.

doest -- (WF) The Greek word translated as "doest" has the primary meaning of "making", "performing" or "producing" something. This word can also be translated as "do" because our English words for "make" and "produce" are not as versatile as the Greek word. However, "do" covers more ground than the Greek word does. The form of this verb is an adjective, not an active verb, so "performing". The form of the adjective is possessive so the sense is "your performing".

alms, -- The Greek word translated as "alms" is the Greek source for our word "eleemosynary," which in English means "charitable". However, the Greek word primarily means "pity" or "mercy". It is another form of the word used in the Beatitudes as "merciful" and "obtain mercy". It can be translated as any of our synonyms for a charitable act but "donation" or "kindness" works pretty well because in English we say that we "make donations" and "perform kindnesses", which conforms with the Greek verb used here. In contrast, we "give alms".

let -- This "let" is the helping verb used to translate the Greek form of the third-person command. In English all commands are in the second-person. This form is used as something like our word "must".

not -- The negative here is the negative of opinion, not fact. It has a sense of something that "shouldn't" or "you don't want" it to be done.

thy -- The word translated as "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours".

missing "the"  -- (MW) The untranslated word is the Greek definite article, "the". The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more. 

left hand -- (CW) The Greek term translated has many negative connotations such as "ominous", "erring" and "awkward". Like the "left" in Latin, it has sinister implications. However, Jesus also uses a different word for "left hand" that has positive implications in phrases such as describing who sits on his left hand.

know -- (CW) The word translated as "know" is one of many Greek different words that are commonly translated as "to know" in the KJV. To distinguish among them, we usually translated this particular word as "learn to know" or, simply, "learn", which is the way that Christ normally uses it. The Greek form of this verb is one that doesn't occur in English, it is a command given to an object. This form is usually translated as "let" so, in this case, "let it learn".

what --  The Greek term translated as "what" has many uses as a pronoun in Greek. It has a sense of uncertainty in the sense of "something" or "someone" and "universality", "anyone" or "anything".

thy -- The word translated as "thy" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours".

missing "the"  -- (MW) The untranslated word is the Greek definite article, "the." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

right hand --  The Greek term translated as "right hand" has the additional meaning of a "pledge" in Greek in the sense that we make agreements and "shake on it" in English. That meaning  fits very well here.

doeth:  -- The Greek word translated as "doest" has the primary meaning of "making", "performing" or "producing", something. The second appearance of the verb is a different form than the first. It is an active verb that could either be the present tense or the imperfect tense, which indicates an action started in the past.

NIV — word by word

But -- The Greek word translated as "but" joins sentences in an adversarial way or introduces a phrase explaining a cause or condition. Given the odd structure of the phrase it is in, it really works best as something like an "if" explaining an alternative condition. 

when -- (IW) There is nothing that can be translated as "when" in the Greek source.

you --This verse starts with a singular pronoun, "you" but its form is not that of a subject, but the form that is normally translated as "of you" or "your". This form is required by form of the verb. The form is singular, continuing the switch to the singular "you" in the previous verse (Matthew 6:2) from the plural "you" in the verse before that (Matthew 6:1) that began this discussion of rewards for good acts.

give -- (WW) The Greek word translated as "give" has the primary meaning of "making", "performing" or "producing", something. This word can also be translated as "do" because our English words for "make" and "produce" are not as versatile as the Greek word. However, "do" covers more ground than the Greek word does. The form of this verb is an adjective, not an active verb, so "performing". The form of the adjective is possessive so the sense is "your performing".

to the -- (IP) There is nothing that can be translated as "the" in the Greek source.

needy, -- (WW) The Greek word translated as "needy" is the Greek source for our word "eleemosynary", which in English means "charitable", but the Greek word primarily means "pity" or "mercy". It is another form of the word used in the Beatitudes as "merciful" and "obtain mercy". It can be translated as any of our synonyms for a charitable act but "donation" or "kindness" works pretty well because in English we say that we "make donations" and "perform kindnesses", which conforms with the Greek verb used here.

do -- This helping verb is used to create commands, negative statements, and smooth word flow in English, but the Greek could be either a question or a statement. 

not -- The negative here is the negative of opinion, not fact. It has a sense of something that "shouldn't" or "you don't want" it to be done.

let -- This "let" is the helping verb used to translate the Greek form of the third-person command. In English all commands are in the second-person. This form is used as something like our word "must".

your -- The word translated as "your " is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours".

missing "the"  -- (MW) The untranslated word is the Greek definite article, "the". The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more. 

left hand -- (CW) The Greek term translated has many negative connotations such as "ominous", "erring" and "awkward". Like the "left" in Latin, it has sinister implications. However, Jesus also uses a different word for "left hand" that has positive implications in phrases such as describing who sits on his left hand.

know -- (CW) The word translated as "know" is one of many Greek different words that are commonly translated as "to know" in the KJV. To distinguish among them, we usually translated this particular word as "learn to know" or, simply, "learn", which is the way that Christ normally uses it. The Greek form of this verb is one that doesn't occur in English, it is a command given to an object. This form is usually translated as "let" so, in this case, "let it learn".

what --  The Greek term translated as "what" has many uses as a pronoun in Greek. It has a sense of uncertainty in the sense of "something" or "someone" and "universality", "anyone" or "anything".

your -- The word translated as "your" is the genitive form of the singular, second-person pronoun, which is most commonly the possessive form. This pronoun follows the noun so "of yours".

missing "the" -- (MW) The untranslated word is the Greek definite article, "the". The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more. 

right hand -- The Greek term translated as "right hand" has the additional meaning of a "pledge" in Greek in the sense that we make agreements and "shake on it" in English. That meaning fits very well here.

is -- This helping verb indicates the present tense of the verb, which is expressed here as an adjective.

doing,:  -- The Greek word translated as "doing" has the primary meaning of "making", "performing" or "producing", something. The second appearance of the verb is a different form than the first. It is an active verb that could either be the present tense or the imperfect tense, which indicates an action started in the past.